(a) Field of the Invention
The present invention relates to a technology for manufacturing an optical waveguide. More specifically, it relates to a method of manufacturing an optical waveguide which has an end face (optical path conversion mirror) for changing an optical path in a predetermined direction and which is adapted to be mounted on a wiring board or the like.
(b) Description of the Related Art
In recent multilayer wiring boards on which higher-density mounting is demanded, the mounting of optical waveguides thereon is being increasingly employed as one technique for solving problems such as crosstalk between signals and a delay in signal transfer rate. Such an optical waveguide is mounted for the purpose of optically coupling two or more optoelectronic devices (laser diode (light emitting element), photodiode (light receiving element), and the like) which are mounted on a multilayer wiring board.
One form of such an optical waveguide is a high polymer optical waveguide (hereinafter also simply referred to as an “optical waveguide”) in which one or more cores made of a resin material are buried in a sheet-shaped cladding made of a polymer (resin) material (e.g., see Japanese Patent Publication Heisei 7-92338). At an end portion of the optical waveguide, an optical path conversion mirror is provided which can change the optical path of light traveling in the core by, for example, 90°.
As a technique of fabricating an optical waveguide having an optical path conversion mirror, methods described below has been known. In one method, an optical waveguide having an optical path conversion mirror is formed in the following manner: a groove and an inclined plane are formed in a cladding layer; resin is buried in the groove and the inclined plane to form a core having an inclined plane; and the core is covered with a cladding layer (e.g., see Japanese Patent Publication 2003-167175).
There is another method in which an optical waveguide is formed beforehand and then cut with a dicing saw to make an inclined plane serving as an optical path conversion mirror at an end portion of the optical waveguide (e.g., see Japanese Patent Publication Heisei 10-300961).
It should be noted that in one known method of processing an end face of an optical fiber, an optical fiber is cut with a heated blade (see Japanese Patent Publication Heisei 7-294748).
In the method in which a core having an inclined plane is buried in a cladding layer, a precision-machined mold is needed to form a groove and an inclined plane. Accordingly, such a method requires the manufacture of a mold and has a disadvantage that the manufacturing cost of an optical waveguide is high. Further, changing the design of the position or angle of an optical path conversion mirror requires another mold. Thus, such a method has the problem that the design of an optical path conversion mirror cannot easily be changed in terms of cost.
On the other hand, as for the method in which an optical waveguide is cut with a dicing saw to form an optical path conversion mirror, machining speed is low, and mass productivity may therefore be lowered.